Coexpression of alpha-sarcomeric actin, alpha-smooth muscle actin and desmin during myogenesis in rat and mouse embryos I. Skeletal muscle.
Expression of vimentin, desmin, alpha-sarcomeric and alpha-smooth muscle actins in embryonic tissues of rat and mice was examined using an immunohistochemical approach. The results showed a similarity in the expression of desmin and alpha-actin isoforms (alpha-sr and alpha-sm) in skeletal muscle cells during murine feto-embryonic development. In the two species, coexpression of alpha-sr and alpha-sm actins has been observed in cardiomyoblasts, myotomal myoblasts and myotubes. The intensity of alpha-sm actin expression decreased during the terminal steps of myogenesis and disappeared completely in mature cardiomyocytes and myofibres. Desmin was expressed in all prefusion myoblasts (type 1 and 2 myoblasts), myotubes, and in myofibres. The appearance of desmin in myoblasts of somites preceded by a few hours the expression of the alpha-actins (alpha-sr and alpha-sm). Our study on vimentin expression, limited to rat embryos, revealed that somite premyoblasts expressed only vimentin, type 1 myoblasts expressed vimentin and desmin, and type 2 myoblasts (rhabdomyoblasts) expressed desmin and alpha-actins (alpha-sr and alpha-sm). Our study demonstrates the resemblance between feto-embryonic myogenesis and myogenic neoplastic differentiation: desmin appears before the alpha-actins in embryonic myoblasts, and can be considered as a marker of an initial step in myogenic differentiation. alpha-sm actin, considered as a striated muscle cell feto-embryonic actin, is expressed transiently in skeletal myoblasts and cardiomyoblasts during development and reappears during neoplastic transformation of skeletal muscle.
Babai
F
F
Département de Pathologie, Université de Montréal C.P. 6128, Succ. A Montréal, Québec, Canada.
Musevi-Aghdam
J
J
Schurch
W
W
Royal
A
A
Gabbiani
G
G
D000199:Actins / Q000235:genetics* / Q000378:metabolism; D000818:Animals; D003893:Desmin / Q000235:genetics* / Q000378:metabolism; D005260:Female; D015870:Gene Expression; D007150:Immunohistochemistry; D051379:Mice; D009132:Muscles / Q000196:embryology / Q000378:metabolism*; D011247:Pregnancy; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D011916:Rats, Inbred F344; D014746:Vimentin / Q000235:genetics / Q000378:metabolism
D000199:Actins; D003893:Desmin; D012333:RNA, Messenger; D014746:Vimentin